A regional archeomagnetic model for Europe for the last 3000 years, SCHA.DIF.3K: Applications to archeomagnetic dating

Pavón-Carrasco, Fco. Javier; Osete, M. L.; Torta, J. M.; Gaya–Piqué, Luis R.

doi:10.1029/2008gc002244

Cited by 136 publications

(167 citation statements)

References 62 publications

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“…The solution to such an inverse problem involving noisy observations is not-unique (Parker 1994). It is, however, possible to find a suitable solution by minimization of an objective functional (m) containing two terms, the first Q(m) that corresponds to some measure of the misfit between the observations and the model predictions (d − f (m)), and the second R(m) that measures the complexity of the model (e.g.…”

Section: Inversion Proceduresmentioning

confidence: 99%

“…Parker 1994;Gubbins 2004). The relation between the observed data d and model parameters m may be expressed in vector notation as…”

Section: Inversion Proceduresmentioning

confidence: 99%

“…Claerbout & Muir 1973;Scales et al 1988;Farquharson & Oldenburg 1998;Tarantola 2005). The L 1 norm measure of misfit has been successfully employed in geomagnetic field modelling of recent and historical data Lesur et al 2008;Finlay et al 2012) and regional archeomagnetic field models (Pavón-Carrasco et al 2009), but it has not previously been tested in the construction of global field models on millennial time scales.…”

Section: Introductionmentioning

confidence: 99%

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Limitations in paleomagnetic data and modelling techniques and their impact on Holocene geomagnetic field models

Panovska

Korte

Finlay

et al. 2015

Geophysical Journal International

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S U M M A R YCharacterization of geomagnetic field behaviour on timescales of centuries to millennia is necessary to understand the mechanisms that sustain the geodynamo and drive its evolution. As Holocene paleomagnetic and archeomagnetic data have become more abundant, strategies for regularized inversion of modern field data have been adapted to produce numerous timevarying global field models. We evaluate the effectiveness of several approaches to inversion and data handling, by assessing both global and regional properties of the resulting models. Global Holocene field models cannot resolve Southern hemisphere regional field variations without the use of sediments. A standard data set is used to construct multiple models using two different strategies for relative paleointensity calibration and declination orientation and a selection of starting models in the inversion procedure. When data uncertainties are considered, the results are similar overall regardless of whether we use iterative calibration and reorientation, or co-estimation of the calibration and orientation parameters as part of the inversion procedure. In each case the quality of the starting model used for initial relative paleointensity calibration and declination orientation is crucial and must be based on the best absolute information available. Without adequate initial calibration the morphology of dipole moment variations can be recovered but its absolute value will be correlated with the initial intensity calibrations, an effect that might be mitigated by ensuring an appropriate fit to enough high quality absolute intensity data with low uncertainties. The declination reorientation mainly impacts regional field structure and in the presence of non-zonal fields will result in a non-zero local average. The importance of declination orientation is highlighted by inconsistencies in the West Pacific and Australian sediment records in CALS10k.1b model. Great care must also be taken to assess uncertainties associated with both paleomagnetic and age data and to evaluate the effects of poor data distribution. New consistently allocated uncertainty estimates for sediment paleomagnetic records highlight the importance of adequate uncertainties in the inversion process, as they determine the relative weighting among the data and overall normalized misfit levels which in turn influence the complexity of the inferred field models. Residual distributions suggest that the most appropriate misfit measure is the L 1 norm (minimum absolute deviation) rather than L 2 (least squares), but this seems to have relatively minor impact on the overall results. For future Holocene field modelling we see a need for comprehensive methods to assess uncertainty in individual archeomagnetic data so that these data or models derived from them can be used for reliable initial relative paleointensity calibration and declination orientation in sediments. More work will be needed to assess whether co-estimation or an iterative approach to inversion is more efficient overall...

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Section: Inversion Proceduresmentioning

confidence: 99%

“…Parker 1994;Gubbins 2004). The relation between the observed data d and model parameters m may be expressed in vector notation as…”

Section: Inversion Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Limitations in paleomagnetic data and modelling techniques and their impact on Holocene geomagnetic field models

Panovska

Korte

Finlay

et al. 2015

Geophysical Journal International

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“…Besides the geodynamic significance, connections between the geomagnetic field and global climate have been suggested (Courtillot et al, 2007;Gallet et al, 2005;Kent, 1982), but these claims remain controversial (Bard and Delaygue, 2008). Furthermore, archaeomagnetic studies focusing on the detailed evolution of the geomagnetic field over the past ∼8 kyr have a potential application on archaeomagnetic dating (Ben-Yosef et al, 2008bPavón-Carrasco et al, 2009.…”

Section: Introductionmentioning

confidence: 99%

Geomagnetic intensity variations for the past 8 kyr: New archaeointensity results from Eastern China

Cai

Tauxe

Deng

et al. 2014

Earth and Planetary Science Letters

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In this study, we have carried out paleointensity experiments on 918 specimens spanning the last ∼7 kyr, including pottery fragments, baked clay and slag, collected from Shandong, Liaoning, Zhejiang and Hebei Provinces in China. Approximately half of the specimens yielded results that passed strict data selection criteria and give high-fidelity paleointensities. The virtual axial dipole moments (VADMs) of our sites range from ∼2 × 10 22 to ∼13 × 10 22 Am 2 . At ∼2250 BCE our results suggest a paleointensity low of ∼2 × 10 22 Am 2 , which increases to a high of ∼13 × 10 22 Am 2 by ∼1300 BCE. This rapid (less than 1000 yrs) six-fold change in the paleointensity may have important implications for the dynamics of core flow at this time. Our data from the last ∼3 kyr are generally in good agreement with the ARCH3k.1 model, but deviate significantly at certain time periods from the CALS3k.4 and CALS10k.1b model, which is likely due to differences in the data used to constrain these models. At ages older than ∼3 ka, where only the CALS10k.1b model is available for comparison, our data deviate significantly from the model. Combining our new results with the published data from China and Japan, we provide greatly improved constraints for the regional model of Eastern Asia. When comparing the variations of geomagnetic field in three global representative areas of Eastern Asia, the Middle East and Southern Europe, a common general trend of sinusoidal variations since ∼8 ka is shown, likely dominated by the dipole component. However, significant disparities are revealed as well, which we attribute to non-dipolar components caused by movement of magnetic flux patches at the core-mantle boundary.

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“…Korte et al, 2009Licht et al, 2013), regional models (e.g. Pavón-Carrasco et al, 2009, or secular variation curves (e.g. Tema and Kondopoulou, 2011) is also widely used for dating purposes.…”

Section: Introductionmentioning

confidence: 99%

Directional changes of the geomagnetic field in West Africa: Insights from the metallurgical site of Korsimoro

Donadini

Serneels

Kapper

et al. 2015

Earth and Planetary Science Letters

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A regional archeomagnetic model for Europe for the last 3000 years, SCHA.DIF.3K: Applications to archeomagnetic dating

Cited by 136 publications

References 62 publications

Limitations in paleomagnetic data and modelling techniques and their impact on Holocene geomagnetic field models

Limitations in paleomagnetic data and modelling techniques and their impact on Holocene geomagnetic field models

Geomagnetic intensity variations for the past 8 kyr: New archaeointensity results from Eastern China

Directional changes of the geomagnetic field in West Africa: Insights from the metallurgical site of Korsimoro

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